Those protesters on Monday night called on Prime Minister Benjamin Netanyahu to reach a cease-fire and hostage release deal after the deaths of six hostages held by Hamas.
Among those hostages found murdered over the weekend in a Hamas-controlled underground tunnel in Gaza was 23-year-old Israeli-American Hersh Goldberg-Polin, whose parents are from the Chicago area.
Jon Polin and Rachel Goldberg said they hoped the next time they addressed a crowd, it would be with their son at their side.
"We became absolutely certain that you were coming home to us alive, but it was not to be," Hersh's mother, Rachel Goldberg, said on Monday. "For 23 years, I was privileged to have the most stunning honor to be Hersh's mama. I'll take it and say thank you. I just wish it had been for longer," she said.
Thousands lined the streets in Jerusalem Monday for his funeral.
"Hersh, we failed you. We all failed you," said Jon Polin, Hersh's father. "Maybe, just maybe, your death is the stone, the fuel to bring home the remaining 101 hostages."
READ MORE | Chicago area mourns death of Israeli-American hostage Hersh Goldberg-Polin
Hersh's mother broke down in tears as she said goodbye to her son, who spent more than 300 days in captivity.
"Finally, my sweet boy, finally, finally, finally, finally! You're free!" she said. "I will love you, and I will miss you every single day for the rest of my life. But you're right here. I know you're right here. I just have to teach myself to feel you in a different way."
CEO and President of the Jewish United Fund of Metropolitan Chicago Lonnie Nasatir met with Hersh's mother in Israel a few weeks ago.
He said he also hopes that a ceasefire deal is met, and remaining hostages will be brought home.
"All leaders of free countries should be putting great pressure on Hamas to give up and say, 'no more!,'" Nasatir said.
SEE ALSO | Who were the 6 hostages whose bodies were recovered from Gaza?
In April, a Hamas-issued video showed Hersh with his left hand missing and clearly speaking under duress, sparking new protests in Israel at the time to urge the government to do more to secure his and others' freedom.
At his first news conference since the recovery of those six hostages, Netanyahu asked their families for forgiveness.
He said his government was close to a deal to bring them home but did not succeed.
"These murderers executed six of our hostages. They shot them in the back of the head. That's what's changed. And now after this, we're asked to show seriousness? We're asked to make concessions? What message does this send Hamas?" Netanyahu said.
The Associated Press contributed to this report.